Amino amide salts of organic monocarboxylic acids as additives for reducing carburetor deposits



United States Patent AMINO AMIDE SALTS OFORGANIC MONOCAR- 'BOXYLIC ACIDSAS ADDITIVES FOR REDUC- ING CARBURETOR DEPOSITS Eddie G. Lindstrom,Martinez, and Maurice R. 'Barusch,

Richmond, Calif., assignors to California Research Corporation, SanFrancisco, Calif., a corporation of Delaware No Drawing. ApplicationFebruary 26, 1958 7 Serial No. 717,571

11 Claims. (Cl. 44-66) This invention relates to an improved hydrocarbonfuel composition suitable for operation in a spark-ignition internalcombustion engine, and particularly to a gasoline composition containinga unique addition agent which functions to reduce deposits in theinduction system of spark-ignition engines.

In certain types of automotive engine service, rough idling and enginestalling has long been a consistent problem and has required frequentcarburetor adjustments and reconditioning in order to'maintainsatisfactory operation. This problem of poor idling operation has beenaccentuated and expanded with the increased traflic density inmetropolitan areas and the use of multi-throat carburetors in privateautomobiles. It has been determined that a primary factor in poor idlingoperation is an accumulation of deposits in the throttle body section ofthe carburetor which causes an over-rich mixture at idle and a reductionin idle speed. The accumulation of deposits in the induction system ofthe engine and, especially, in the throttle section of the carburetor isparticularly pronounced in services requiring considerable idling, suchas taxicab and door-to-door delivery service. In private automobileoperation, this problem is particularly emphasized in the metropolitanareas where heavy city traflic is encountered with appreciablestop-and-go driving. The critical accumulation point for these depositsis adjacent to the throttle plate, whose position controls the .air-fuelratio. As these deposits accumulate, the air flow at idle is restrictedwith no change in fuel flow, and a rich mixture results causing erraticidling and engine stalling. In order to compensate for the presence ofthese deposits,

the throttle must be opened slightly by increasing the idle speedadjustment which, although allowing more air flow,

v automatically supplies more fuel. This requires a fuel correction bychanging the idle mixture adjustment'screw a compensating amount. Theamount of idle adjustment required to maintain satisfactory idleperformance is an indica-tion of the deposit build-up. Furthermore,deposits will often form in the idle air passageway causing restrictionwhich allows the manifold vacuum to draw more gasoline into the engine,again causing rich idle and engine stalling. It has been establishedthat the primary source'of these deposits is the contaminants in theintake air of the engine when operating at idle. The greatest source ofthese intake air contaminants is engine blowby, which accounts forapproximately one-half of the deposits. Exhaust from other vehicles,dust, and other components classed as normal air pollutants contributeto the formation of deposits.

The hydrocarbon components of the gasoline fuel bear no direct relationto the formation of these deposits. Tests I have indicated that unstableor aged gasolines having a 2,922,707, Patented ,Jan. 2 1

7 presence of the carburetor and induction system deposits,

it has now been found possible to provide a fuel composition which iscapable of preventing an accumulation or build-up of these deposits andwill also function to reduce the existing deposits. Thus, by operating aspark-ignition engine with a fuel composition compounded in accordancewith the present invention it is possible to materially improve theidling operation of the engine and sustain this improved operation evenunder adverse conditions of intake air pollution.

It has been discovered and claimed in the copendin application SerialNo. 424,243 of the applicants, that the incorporation in a hydrocarbonbase fuel, boiling within the gasoline boiling range, of a small amountof an oilsoluble aliphatic-substituted amino alkylene amide, and

"preferably an acyclic amino alkylene amide containing an aliphaticradical, such as an alkyl radical of less than 5 carbonratoms, andpreferably of 2 to 4 carbon atoms, attached to the amino group, willprovide a fuel composition which will effectively inhibit the build-upof deposits in the carburetor of an engine operated thereon. Inaddition, a gasoline composition containing this improving agentsubstantially reduce and prevent the formation of deposits throughoutthe area of the air-fuel induction system of the engine.

A particular class of compounds which function as the above uniqueimproving agents may be represented by the following general formula: V

I in which R is an acyclic hydrocarbon radical containing 11 to 17carbon atoms, A is an alkylene radical and preferably an alkyleneradical containing 2 to 4 carbon atoms,

and in the two occurrences of R one is hydrogen and the other is analiphatic radical containing 4 and fewer carbon atoms, such as an alkyl,a hydroxyalkyl, or an aminoalkyl radical. It will be noted that thealternate positions of the aliphatic radical R in Formula I arerepresentative of the isomeric forms of the compound, both of which arenormally present to a greater or lesser extent, depending upon .thereaction employed in the preparation of these compounds. These isomericforms may be conveniently referred to as a linear amino amide withreference to the form: r

and as an amino tertiary amide with respect to the following form:

Q contrast to the pericxiic mechanical adjustments and,

as to control the condensation to the elimination of one mol of water.The higher fatty acid component of the reaction may be an acid such aslauric, myristic, palrnitic, stearic, linoleic or oleic acid, while thepolyamine reactant may be a polyalkylene polyamine or an N-(alkyl-.eneoxide) derivative of an alkylene diamine. In ,all

' able for practical applications.

- 0.0003 to 1.5 percent by weight.

instances, the alkylene group is preferably an ethylene, propylene orbutylene group. Other methods of preparing the amides of theinventionmay also be employed. v r

. It is usually desirable to prepare or formulate the improving agentsof the invention in the form of a concentrate to facilitate handlingproblems and permit a simple blending operation in the incorporation ofthe additive in the fuel. In the preparation of the concentrate, theimproving agent is dissolved in a hydrocarbon solvent, and particularlyan aromatic solvent, in a concentration range of at least 10 percent byweight and up to about "70 percent by weight.

The improving agents of the invention, hy rea'son of their uniqueeifectiveness, are incorporated in the hyfd'rocarbon base fuel inrelatively small amounts and preferably within the range of about 0.0003to 0.1 percent by weight. .ployed, their efiectiveness insofar as thereduction of carburetor deposit build-up does not materially improvewith additional concentration of the additive.

While the foregoing description of the improving agents of the inventionis directed to the free amino amide compounds, certain modifications incomposition of the agents may be employed to advantage. Thus, the saltsof' the amino amide with organic and inorganic acids may be used toprovide added improving characteristics to the agents and to thegasoline compounded therewith.

Among the various classes of organic acid salts of the amino alkyleneamides which may be used as additives to gasoline in accordance with thepresent invention, an eminently suitable class of salts is that of saltsof organic monocarboxylic acids (aliphatic, cycloaliphatic andaromatic). A particularly efiective class, because of the case ofpreparation and effectiveness in reducing deposits, is formed by saltsof saturated C -C aliphatic monocarboxylic acids and salts ofunsaturated C -C aliphatic monocarboxylic acids having one doublecarbon-to-carbon bond in the hydrocarbon portion of their molecule.Among the salts of these latter, salts of monoalkenoic (mono-olefinic)monocarboxylic acids containing 4 or more carbon atoms are preferred,whereas among salts of saturated aliphatic (alkanoic) acids, thosecontaining 1 to 4 carbon atoms are particularly suit- Formates areparticularly effective and desirable as additives to gasoline accordingto the invention.

As illustrative examples of suitable salts, there may be mentioned theamide salts of formic, acetic, butyric, isobutyric, valeric, caproic,pelargonic, lauric, myristic, myristoleic, palmitoleic, stearic, oleic,palmitic, isovaleric, arachidic acid, and the like. Certain advantagesmay furthermore be gained, in appropriate cases, by using amino amidesalts of mixtures of the aliphatic monocarboxylic acids and aromaticmonocarboxylic acids and/ or hydroxy-substituted aliphaticmonocarboxylic acids. When the improving agents are employed in the formof their salts and particularly as a multi-functional agent, theconcentration of the additives in the gasoline may vary over a widerrange such as, for example, from Amounts in the range from 0.01 to 1.0percent by weight are preferred in ordinary practical applications.

In addition to the subject improving agents in the "fuel composition,other conventional fuel additives may be incorporated. An added factorin the reduction of deposits within the air-fuel induction system of theengine may be obtained by the incorporation, in combination with thesubject improving agents, of a nonvolatile oil, such as a light minerallubricating oil or a petroleum spray oil, which functions as a carrierfor the deposits dispersed by the amino amide improving agents.Satisfactory results have been obtained by incorporating a nonvolatileoil in the range of between :05 to 0.5 per- Although largerconcentrations may be em- '4 cent by volume and have shown effectivenessin the reduction of deposits in the area of the intake ports of theengine.

The following examples are presented to illustrate the preparation andunique deposit-reducing characteristics of representative improvingagents of the invention.

Example I This example illustrates the general procedure for thepreparation of the aminoalkylene amide addition to gasoline. 100 grams(0.96 mol) of aminoethylethanolamine, 100 grams (0.34 mol) of methyloleate, and 75 ml. of benzene were charged to a reaction flask fittedwith a 12-inch fractionating column packed with glass helices. Thereaction temperature was held at 110 to 120 C. while methanol wasremoved through the column as a benzene azeotrope distilling at 59 C.The reaction was continued until methanol formation was complete, whichrequired about 10 hours. J

Thereaction product was dissolved in 3 volumes of equal parts of benzeneand mixed hexanes. The solution was washed four times with 10 percentaqueous sodium chloride solution to remove excess diamine. The solventswere removed onthe steam plate and a solid waxy product resulted oncooling.

Titration of a product sample with hydrochloric acid using a Beckmanglass electrode pH meter indicated that the product was substantiallyamino alkylene amide.

The reaction product was dissolved in benzene, filtered, and solventremoved to a 115 C. pot temperature at 2 millimeters pressure. 116 gramsof product having an equivalent weight of 479 were recovered. Thisindicates that the total amino amide content was 77 percent based on acalculated equivalent weight of 369. The neutral impurity is probablymethyl oleate. The product was chosen as a typical amino amide materialof the invention for the preparation of salts of organic monocarboxylicacids.

By subsequent conventional purification techniques (repeatedrecrystallizations), pure linear amino amide may be recovered from thiscrude amide mixture. Suitable modifications of the reaction conditionspermits of Example 11 The amide propionate was prepared in astraightforward manner by intimately mixing a solution containing about53% of mono-oleoyl amide of N-2-hydroxyethyl- 1,2-ethylenediamine, 35%of an aromatic hydrocarbon thinner (boiling from 316 to 330 F.), 4% ofn-butanol and 5% by weight of water, with an equivalent amount ofpropionic acid (based on the amide content in the concentrate). Themixture was thoroughly stirred to assure uniform reaction.

Other amide salts of aliphatic monocarboxylic acids were prepared andrecovered in a similar fashion as liquid to soft wax-like products, andthen tested for their deposit-reducing ability in accordance with theprocedure described in the next example.

Example III A laboratory test was developed to correlate the formationof carburetor deposits with field experience. In this test, a glassthrottle body is inserted between the float section and the cast ironthrottle body of a conventional carburetor. This glass throttle body isa section of glass tubing A-inch thick, approximately 1% inches insidediameter, and about 2 inches long. About A-inch down from the upperedge, holes are drilled diametrically to receive a conventional metalthrottle plate and shaft. The carburetor and engine employed in the testare those of a 1952 Plymouth. I

The engine is started with the throttle plate in the cast iron bodycontrolling the speed, and the throttle plate in theglass body wideopen. When the engine'is warmed up'so that no danger of backfiringexists, the throttle in the glass body is made to assume the throttlingfunction, and the plate in the iron body is opened wide. Two small tubescarry the idle mixture from the float section to appropriate passagewaysin the cast iron throttle body.

The engine is operated a total of two hours on the test gasoline atabout 500 r.p.m. idle, with five full thro ttle, no-load accelerations,up to a speed of about 3,000 r.p.m. every 15 minutes during the testperiod. During each run, all of the engine blowby is piped to theengines air cleaner atop the carburetor. At the end of the test run, theengine is shut down and the glass throttle body removed and rated inaccordance with the degree of deposits on a scale ranging from 1 to 7. Arating of 1 indicates a complete lack of deposits with the throttle bodyclean, and a rating of 7 indicates substantially complete coverage withblack, opaque deposits. This test procedure and the rating of compoundedgasolines obtained thereby have found excellent correlation with actualtest operations in the field.

Several representative amino amide carboxylate salts were tested asdescribed hereinabove, and the results of the following tabulationillustrate the beneficial depositreducing action of these salts inaccordance with the invention.

1 All deposit ratings corrected to a base fuel rating of 6.0.

The base fuel employed Was a commercial leaded regular gasoline which isrepresentative of nationally-available commercial gasolines. As waspreviously mentioned, the hydrocarbon composition of the base fuel has anegligible effect upon the formation of carburetor deposits except as itinfluences the composition of the blowby, and the test results givenabove on the base fuel will be approximately the same, irrespective ofthe stability, gum content, or other characteristics of the hydrocarboncomponents of the fuel.

In addition to the foregoing test data, a gasoline compositioncompounded in accordance with the present inventoin was field tested inrepresentative fleet service and private automobile operation over anextended period of time with periodic inspection of the air-fuelinduction systems of the engines and, in particular,'the carburetors. Inall instances, the test fuel not only inhibited the formation ofcarburetor deposits, but also was effective in removing existingdeposits within the carburetor and the intake manifold, and permittedcontinuous satisfactory operation extending beyond periods where,normally, carburetor overhauling was to be expected.

Obviously, many modifications and variations of the invention, ashereinbefore set forth, may be made without departing from the spiritand scope thereof, and therefore only such limitations should be imposedas are indicated in the appended claims.

This application is a continuation-in-part of our copending applicationSerial No. 424,243, filed on April 19, 1954, and issued as US. PatentNo. 2,839,372 on June 17, 1958.

We claim:

1. An improved gasoline composition which comprises a major portion of ahydrocarbon base fuel boiling within the gasoline boiling range, havingincorporated therein from about 0.0003 to about 1.5% by weight of a saltV and of a (T -Cg aliphatic monocarbo'xylic acid and an acyclic aminoalkylene amide of the following formula;

11 to 17 carbon atoms, A is an alkylene radical containing 2 to 4 carbonatoms, and inthe two occurrences of -R' one is hydrogen and the other isan aliphatic radical containing 4 and fewer carbon atoms and selectedfrom the group consisting of alkyl,hydroxyalkyl and aminoalkyl radicals.I

2. An improved gasoline composition which comprises a major portion of ahydrocarbon base fuel boiling within the gasoline boiling range, havingincorporated therein from about 0.0003 to about 1.5% by weight of a saltof a c c 'aliphatic monocarboxylic acid and a mixture of amides of thefollowing formulas:

wherein R is an acyclic hydrocarbon radical containing 11 to 17 carbonatoms, A is an alkylene radical containing 2 to 4 carbon atoms, and R isan aliphatic radical containing 4 and fewer carbon atoms and selectedfrom the group consisting of alkyl, hydroxyalkyl and aminoalkylradicals.

3. An improved gasoline composition which comprises a hydrocarbon basefuel boiling within the gasoline boiling range, having incorporatedtherein about 0.0003 to about 1.5 percent by weight of a salt of asaturated C C aliphatic monocarboxylic acid and an acyclic oil-solublealiphatic-substituted amino alkylene amide of the following formula:

wherein R is an acyclic hydrocarbon radical containing 11 to 17 carbonatoms, A is an alkylene radical containing 2 to 4 carbon atoms, and inthe two occurrences of R one is hydrogen and the other is an aliphaticradical containing 4 and fewer carbon atoms and selected from the groupconsisting of alkyl, hydroxyalkyl and aminoalkyl radicals.

4. An improved gasoline composition which comprises a hydrocarbon basefuel boiling within the gasoline boiling range, having incorporatedtherein about 0.0003 to about 1.5 percent by weight of a salt of a C -Cmonoalkenoic monocarboxylic acid and an acyclic oil-solublealiphatic-substituted amino alkylene amide of the following formula:

wherein R is an acyclic hydrocarbon radical containing 11 to 17 carbonatoms, A is an alkylene radical containing '2 to 4 carbon atoms, and inthe two occurrences of R one is hydrogen and the other is an aliphaticradical containing 4 and fewer carbon atoms and selected from the groupconsisting of alkyl, hydroxyalkyl and aminoalkyl radicals.

5. The gasoline composition of claim 1 containing, in addition, 0.05 to0.5 percent by volume of a nonvolatile oil.

bon solvent boiling substantially within the gasoline boiling range andhaving dissolved therein an amount ranging from about 10 to about 70% byweight of a salt of a C -C aliphatic monocarboxylic acid and anoil-soluble acyclic amino alkylene amide of the formula R-ii-if-A-NHRwherein R is 'an acyclic hydrocarbon radical containing 11 to 17 carbonatoms, A is an alkylene radical con- .taining 2 to 4 carbon atoms, andin the two occurrences of R one is hydrogen and the other is analiphatic radical containing 4 and fewer carbon atoms and selected fromthe group consisting of alkyl, hydroxyalkyl and aminoalkyl radicals. V

7. An additive concentrate as defined in claim 6, where- :inthe salt ofa C -C aliphatic monocarboxylic acid is a salt of a saturated C -Caliphatic monocarboxylic acid.

11. An improved gasoline composition which comprises '8 a major portionof a hydrocarbon base fuel boiling with- ;in the gasoline boiling range,having incorporated therein from about 0.0003 to about 1.5% byweightof-a salt of an unsubstituted saturated aliphatic monoca rbo'xylicacid selected from the group of Cr-C saturated aliphatic monocarboxylicacids, the lowest member of which is formic acid and the highest isarachidic acid, and an acycylic amino alkylene amide of the followingformula:

wherein R is an acyclic hydrocarbon radical containing 11 to 17 carbonatoms, A is an alkylene radical containing 2 to 4 carbon atoms, and inthe two occurrences of R one is hydrogen and the other is an aliphaticradical containing 4 and fewer carbon atoms and selected from thegroupconsisting of al-kyl, hydroxyalkyl and aminoalkyl radicals.

References Cited in the file of this patent UNITED STATES PATENTS2,014,924 Benedict Sept. 17, 1935 2,312,082 Dietrich Feb. 23, 19432,340,881 Kelley et al. Feb. 8,1944 2,387,501 Dietrich Oct. 23, 19452,508,924 Mertens et al. May 23, 1950 2,568,876 White et al. Sept. 25,1951

1. AN IMPROVED GASOLINE COMPOSITION WHICH COMPRISES A MAJOR PORTION OF AHYDROCARBON BASE FUEL BOILING WITHIN THE GASOLINE BOILING RANGE, HAVINGINCORPORATED THEREIN FROM ABOUT 0.0003 TO ABOUT 1.5% BY WEIGHT OF A SALTOF A C1-C20 ALIPHATIC MONOCARBOXYLIC ACID AND AN ACYCLIC AMINO ALKYLENEAMIDE OF THE FOLLOWING FORMULA: